As a girl, Amane realizes with horror that her parents “copulated” in order to bring her into the world, rather than using artificial insemination, which became the norm in the mid-twentieth century. Amane strives to get away from what she considers an indoctrination in this strange “system” by her mother, but her infatuations with both anime characters and real people have a sexual force that is undeniable.

As an adult in an appropriately sexless marriage—sex between married couples is now considered as taboo as incest—Amane and her husband Saku decide to go and live in a mysterious new town called Experiment City or Paradise-Eden, where all children are raised communally, and every person is considered a Mother to all children.

Men are beginning to become pregnant using artificial wombs that sit outside of their bodies like balloons, and children are nameless, called only “Kodomo-chan.” Is this the new world that will purify Amane of her strangeness once and for all?